Active Vibration Suppression of a Flexible Beam via Sliding Mode and H∞ Control

In this study, sliding mode and H∞control techniques are applied to a flexible beam in order to suppress some of the vibration modes. The beam is a clamped-free flexible structure having piezoelectric (PZT) patches as actuators and a laser displacement sensor for measuring the tip point deflection. The beam is modeled in two different ways for each control algorithm. To implement sliding mode control (SMC), Euler-Bernoulli beam model is used and a finite dimensional LTI model is formed by using assumed mode method. As the SMC requires state measurement, an observer is designed to estimate the states from the measured tip deflection. In order to implement H∞control algorithm, the model of the flexible beam, which is an approximate transfer function, is constructed by using system identification technique. The experimental results of designed SMC and H∞control algorithms are presented.